Non-destructive testing apparatus and process with simultaneous acquisition of radiographic data and tomographic data

Abstract

Non-destructive testing apparatus and process with the simultaneous acquisition of radiographic data and tomographic data comprises a gamma or X-ray source-detector assembly (2-6), an object support (16) placed between the source and the detector, means (17) for ensuring at least one relative rotary movement of the support with respect to the source-detector assembly, the detector being a bidimensional detector supplying for each point of each radiographic projection an analog signal proportional to the radiation quantity transmitted by the object (4), an analog-digital converter (21) for converting the signals from the detector into digital data, a first memory (28) for storing said digital data, a system (30) for the extraction and accumulation of part of said stored data, corresponding to at least one particular zone of the object to be tested or examined, a second memory (32) for storing the sinograms obtained from the selected and accumulated data and a system for processing these sinograms in order to reconstruct the tomographic sections.

We claim: 
     
       1. Non-destructive testing apparatus with simultaneous acquisition of radiographic projection data for an object and tomographic section data for said object, comprising an ionizing radiation source-detector assembly (2-6), an object support (16) placed between the source and the detector, means (17) for ensuring at least one relative rotary movement of the support relative to the source-detector assembly, the detector being a bidimensional detector with several rows and several columns, supplying for each point of each radiographic projection (P1, . . ., Pj) an analog signal proportional to the radiation quantity transmitted by the object (4), an analog-digital converter (22) for converting the signal supplied by the detector into digital data, a first memory (28) for storing said digital data, a system (30) for the extraction and accumulation of part of said stored data corresponding to at least one particular zone of the object to be tested, a second memory (32) for storing sinograms obtained from the data selected and accumulated by the extraction system and a processing system (36) for said sinograms for the construction of tomographic sections (14). 
     
     
       2. Apparatus according to claim 1, characterized in that the processing system incorporates a computer (36) for the control of the apparatus and the reconstruction of tomographic sections, controlling a display apparatus (26) for the radiographic projections (P1, . . . , Pj) and/or tomographic sections (14) and an access system (40) to said computer. 
     
     
       3. Apparatus according to claim 1, characterized in that a first collimator (15) is provided at the outlet from the source for collimating the radiation (5) from said source for carrying out conventional tomography. 
     
     
       4. Apparatus according to claim 1, characterized in that a second collimator (18) is provided facing the detector in order to serve as a mask for the radiation directly coming from the source. 
     
     
       5. Apparatus according to claim 1, characterized in that there are filing means (38) for the radiographic projections and/or tomographic sections of the object. 
     
     
       6. Apparatus according to claim 1, characterized in that the extraction system (30) incorporates at least two memories, a memory (29) in which are recorded extraction parameters of said part of the data and a memory (31) in which are accumulated the selected rows or columns. 
     
     
       7. Process for the non-destructive testing of an object comprising: a) subjecting said object (4) to ionizing radiation (5) under different incidences, the object having at least one relative rotary movement with respect to the source-detector assembly, each incidence corresponding to a projection,   b) detecting the radiation transmitted by the object with the aid of a bidimensional detector (6) having several rows and columns, supplying at each point analog signals proportional to the radiation quantity transmitted by the object,   c) converting (22) said analog signals into digital data,   d) storing said digital data in a first memory (24),   e) processing (36) the digital data in order to produce radiographic projections (P1, . . . , Pj) of the object,   f) selecting at least one particular zone of the object to be tested,   g) extracting (30) from the first memory the digital data corresponding to said zone and accumulating the same for each projection,   h) producing (32) a sinogram corresponding to said zone from data extracted and accumulated from the different projections and   i) processing (36) said sinogram in order to reconstruct a tamographic section of the object (14) in the selected zone.   
     
     
       8. Process according to claim 7, characterized in that extraction takes place from the first memory of n' rows or columns of each radiographic projection on either side of the row or column of these projections corresponding to the centre of said particular zone and in that they are accumulated column by column or row by row in each projection. 
     
     
       9. Process according to claim 7, characterized in that on a display (26) are displayed the radiographic projections (P1, . . . , Pj) and/or the tomographic sections (14).